An Improved LCL-L Compensation Topology for Capacitive Power Transfer in Electric Vehicle Charging

This paper proposes an LCL-L compensation circuit for high power capacitive power transfer (CPT) aiming at minimizing number of resonant components and improving system performance. The proposed topology adopts only four external resonant components at both sides of the capacitive coupler. The output power is proportional to the capacitive coupling coefficient, therefore, it simplifies the design procedure and abolishes protection circuit requirements under coupler's misalignment. Moreover, optimizing efficiency at full-load conditions of compensation network can be easily achieved in this system by designing resonant components at the highest value of the mutual capacitance. Theoretical analysis of the proposed system is conducted alongside comparison to lasted CPT compensation circuits. Simulation and experimental results of a 1.5-kW CPT prototype with an air gap distance of 150 mm are provided to verify the feasibility and the effectiveness of the proposed system. System performances under different coupler's misalignment conditions and output power levels are also examined and discussed as well.